This invention relates to a rust preventing resin composition for use in protecting metallic structures such as ships, building, machineries and the like made of iron, zinc, aluminum and their alloys.
Anticorrosive or rust preventing paints containing natural tannic acid are known. These paints utilize the ability of tannic acid to form a stable chelate with ion atoms. Examples of tannic acid-containing coating compositions are disclosed in Japanese Patent Publication Nos. 48,43727 and 49-35495, and also Japanese Patent Kokai (laid open) Nos. 51-152475, 57-152476 and 57-139155.
These prior art compositions, however, suffer from certain disadvantages in that they do not fully exhibit the chelate-forming activity of tannic acid with the decrease in rust preventing properties of the entire composition. The weakened chelate-forming activity also affects the adhesive strength of the resulting film so that the film tends to be liable to cracks and peeling off upon exerting mechanical stresses, shocks, heat and the like.
It is, therefore, a principal object of the present invention to provide a rust preventing resin composition comprising natural tannic acid which is free from the abovedescribed disadvantages.
Other objects and advantages will become apparent as the description proceeds.